Fe–Th phases

10 phases (tier A 5, tier C 4, liquid 1); 9 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model).

Data: interactive registry · full JSON · Fe–Th system page · Markdown · field reference

Phases of the Fe–Th system (10)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:fe-th:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–3999.49 K, x(Th) 0–1	10	1
FCC_A1 phase:fe-th:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1667.5 K, x(Th) 0–1	8	1
FE17TH2 phase:fe-th:fe17th2	Th2Zn17 · hR19 · R-3m (166)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 479.4–1735.38 K, x(Th) 0.10526–0.10526	12	1
FE3TH phase:fe-th:fe3th	Ni3Pu · hR12 · R-3m (166)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 461.04–1374.59 K, x(Th) 0.25–0.25	10	1
FE3TH7_D102 phase:fe-th:fe3th7-d102	Fe3Th7 · D10_2 · hP20 · P6_3mc (186)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1212.83 K, x(Th) 0.7–0.7	4	1
FE5TH_D2D phase:fe-th:fe5th-d2d	CaCu5 · D2_d · hP6 · P6/mmm (191)	tier A: standard phase name	stable in 1 of 1 calculated diagram(s): 300–1642.51 K, x(Th) 0.16667–0.16667	4	1
FE7TH2_ALPHA phase:fe-th:fe7th2-alpha	Ce2Ni7 · hP36 · P6_3/mmc (194)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 300–1455.45 K, x(Th) 0.22222–0.22222	4	1
FE7TH2_BETA phase:fe-th:fe7th2-beta	Co7Gd2 · hR18 · R-3m (166)	tier C: assessor-stated (Hallstedt 2025 crystallographic table)	stable in 1 of 1 calculated diagram(s): 1455.45–1495.62 K, x(Th) 0.22222–0.22222	4	1
HCP_A3 phase:fe-th:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	not stable in 1 calculated diagram(s)	0	1
LIQUID phase:fe-th:liquid	liquid	liquid	stable in 1 of 1 calculated diagram(s): 1128.23–4000 K, x(Th) 0–1	22	1

BCC_A2 (Fe–Th)

Id: phase:fe-th:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–3999.49 K, x(Th) 0–1
Literature: 10 values (10 accepted) from 1 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:fe-th:bcc-a2
paper: paper:10.1016/j.jallcom.2007.03.003:(αFe), paper:10.1016/j.jallcom.2007.03.003:αFe, paper:10.1016/j.jallcom.2007.03.003:βTh, paper:10.1016/j.jallcom.2007.03.003:δFe
tdb: tdb:FeTh-08Wan.tdb:BCC_A2

TDB models of BCC_A2 (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: BCC_A2, type code %B, sha256 ef83b175033c76d1…

33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : FE% TH% : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FCC_A1 (Fe–Th)

Id: phase:fe-th:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 300–1667.5 K, x(Th) 0–1
Literature: 8 values (8 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:fe-th:fcc-a1
paper: paper:10.1016/j.jallcom.2007.03.003:(αTh), paper:10.1016/j.jallcom.2007.03.003:αTh, paper:10.1016/j.jallcom.2007.03.003:γFe
tdb: tdb:FeTh-08Wan.tdb:FCC_A1

TDB models of FCC_A1 (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FCC_A1, type code %A, sha256 ef83b175033c76d1…

28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : FE% TH% : VA : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FE17TH2 (Fe–Th)

Id: phase:fe-th:fe17th2; status assigned
Structure: Th2Zn17 · hR19 · R-3m (166); type st:th2zn17-hr19; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) doi:10.1016/j.calphad.2025.102833
Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Fe 0.8947, Th 0.1053
Stability: stable in 1 of 1 calculated diagram(s): 479.4–1735.38 K, x(Th) 0.10526–0.10526
Literature: 12 values (12 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:fe-th:fe17th2
paper: paper:10.1016/j.jallcom.2007.03.003:Fe17Th2
tdb: tdb:FeTh-08Wan.tdb:FE17TH2

TDB models of FE17TH2 (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE17TH2, type code %A, sha256 ef83b175033c76d1…

43: PHASE FE17TH2 %A 2 17 2 !
44: CONST FE17TH2 : FE : TH : !

Example references (3 of 3; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase
doi:10.1007/bf02645589 W. H. Skelton, N. J. Magnani, J. F. Smith, Thermodynamics of formation of th-fe alloys, Metall Trans 4, 917-920 (1973).
cited as the source of values for this phase

FE3TH (Fe–Th)

Id: phase:fe-th:fe3th; status assigned
Structure: Ni3Pu · hR12 · R-3m (166); type st:ni3pu-hr12; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) doi:10.1016/j.calphad.2025.102833
Caveat: not certain from the name or DFT alone (no_on_hull_entry_in_both, no_structure_token); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Fe 0.7500, Th 0.2500
Stability: stable in 1 of 1 calculated diagram(s): 461.04–1374.59 K, x(Th) 0.25–0.25
Literature: 10 values (10 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:fe-th:fe3th
paper: paper:10.1016/j.jallcom.2007.03.003:Fe3Th
tdb: tdb:FeTh-08Wan.tdb:FE3TH

TDB models of FE3TH (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE3TH, type code %A, sha256 ef83b175033c76d1…

63: PHASE FE3TH %A 2 3 1 !
64: CONST FE3TH : FE : TH : !

Example references (3 of 3; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1007/bf02645589 W. H. Skelton, N. J. Magnani, J. F. Smith, Thermodynamics of formation of th-fe alloys, Metall Trans 4, 917-920 (1973).
cited as the source of values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FE3TH7_D102 (Fe–Th)

Id: phase:fe-th:fe3th7-d102; status assigned
Structure: Fe3Th7 · D10_2 · hP20 · P6_3mc (186); type st:d10-2-fe3th7-hp20; tier A: standard phase name; confidence high
Caveat: DFT agrees: on-hull mp-aaaabaqw and oqmd-18700, space group 186
Stoichiometry: Fe 0.3000, Th 0.7000
Stability: stable in 1 of 1 calculated diagram(s): 300–1212.83 K, x(Th) 0.7–0.7
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:fe-th:fe3th7-d102
mp: mp:mp-aaaabaqw
oqmd: oqmd:oqmd-18700
paper: paper:10.1016/j.jallcom.2007.03.003:Fe3Th7
tdb: tdb:FeTh-08Wan.tdb:FE3TH7_D102

TDB models of FE3TH7_D102 (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE3TH7_D102, type code %, sha256 ef83b175033c76d1…

68: PHASE FE3TH7_D102 % 2 3 7 !
69: CONST FE3TH7_D102 : FE : TH : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FE5TH_D2D (Fe–Th)

Id: phase:fe-th:fe5th-d2d; status assigned
Structure: CaCu5 · D2_d · hP6 · P6/mmm (191); type st:d2-d-cacu5-hp6; tier A: standard phase name; confidence high
Caveat: DFT agrees: on-hull mp-aaaaadzl and oqmd-19306, space group 191
Stoichiometry: Fe 0.8333, Th 0.1667
Stability: stable in 1 of 1 calculated diagram(s): 300–1642.51 K, x(Th) 0.16667–0.16667
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:fe-th:fe5th-d2d
mp: mp:mp-aaaaadzl
oqmd: oqmd:oqmd-19306
paper: paper:10.1016/j.jallcom.2007.03.003:Fe5Th
tdb: tdb:FeTh-08Wan.tdb:FE5TH_D2D

TDB models of FE5TH_D2D (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE5TH_D2D, type code %A, sha256 ef83b175033c76d1…

48: PHASE FE5TH_D2D %A 2 5 1 !
49: CONST FE5TH_D2D : FE : TH : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FE7TH2_ALPHA (Fe–Th)

Id: phase:fe-th:fe7th2-alpha; status assigned
Structure: Ce2Ni7 · hP36 · P6_3/mmc (194); type st:ce2ni7-hp36; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) doi:10.1016/j.calphad.2025.102833
Caveat: not certain from the name or DFT alone (no_structure_token, polymorph_family:other phases of this system have the same composition); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Fe 0.7778, Th 0.2222
Stability: stable in 1 of 1 calculated diagram(s): 300–1455.45 K, x(Th) 0.22222–0.22222
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (4): corpus: corpus:phase:fe-th:fe7th2-alpha
paper: paper:10.1016/j.jallcom.2007.03.003:aFe7Th2, paper:10.1016/j.jallcom.2007.03.003:αFe7Th2
tdb: tdb:FeTh-08Wan.tdb:FE7TH2_ALPHA

TDB models of FE7TH2_ALPHA (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE7TH2_ALPHA, type code %A, sha256 ef83b175033c76d1…

53: PHASE FE7TH2_ALPHA %A 2 7 2 !
54: CONST FE7TH2_ALPHA : FE : TH : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

FE7TH2_BETA (Fe–Th)

Id: phase:fe-th:fe7th2-beta; status assigned
Structure: Co7Gd2 · hR18 · R-3m (166); type st:co7gd2-hr18; tier C: assessor-stated (Hallstedt 2025 crystallographic table); confidence assessor-stated
Structure source: B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, supplementary crystallographic table (mmc2) doi:10.1016/j.calphad.2025.102833
Caveat: not certain from the name or DFT alone (no_structure_token, polymorph_family:other phases of this system have the same composition); structure as stated in the SGTE crystallographic table for this phase name and system
Stoichiometry: Fe 0.7778, Th 0.2222
Stability: stable in 1 of 1 calculated diagram(s): 1455.45–1495.62 K, x(Th) 0.22222–0.22222
Literature: 4 values (4 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:fe-th:fe7th2-beta
paper: paper:10.1016/j.jallcom.2007.03.003:βFe7Th2
tdb: tdb:FeTh-08Wan.tdb:FE7TH2_BETA

TDB models of FE7TH2_BETA (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: FE7TH2_BETA, type code %A, sha256 ef83b175033c76d1…

58: PHASE FE7TH2_BETA %A 2 7 2 !
59: CONST FE7TH2_BETA : FE : TH : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

HCP_A3 (Fe–Th)

Id: phase:fe-th:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stoichiometry: Fe 1.0000
Stability: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:fe-th:hcp-a3
tdb: tdb:FeTh-08Wan.tdb:HCP_A3

TDB models of HCP_A3 (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: HCP_A3, type code %A, sha256 ef83b175033c76d1…

38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : FE : VA : !

Example references (1 of 1; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase

LIQUID (Fe–Th)

Id: phase:fe-th:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 1 of 1 calculated diagram(s): 1128.23–4000 K, x(Th) 0–1
Literature: 22 values (22 accepted) from 1 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:fe-th:liquid
paper: paper:10.1016/j.jallcom.2007.03.003:L
tdb: tdb:FeTh-08Wan.tdb:LIQUID

TDB models of LIQUID (1): PHASE and CONSTITUENT statements as written

FeTh-08Wan.tdb: LIQUID, type code %, sha256 ef83b175033c76d1…

23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : FE TH : !

Example references (2 of 2; assessments first):

doi:10.1016/j.jallcom.2007.03.003 C.P. Wang, P. Yu, X.J. Liu, I. Ohnuma, R. Kainuma, K. Ishida, Thermodynamic assessment of the Co–Th and Fe–Th systems, Journal of Alloys and Compounds 457, 150-156 (2008).
assessment that models this phase; reports values for this phase
doi:10.1016/0022-5088(89)90170-7 A. Palenzona, S. Cirafici, The equilibrium diagrams of the Th-Fe and Th-Co systems, Journal of the Less Common Metals 154, 61-66 (1989).
cited as the source of values for this phase

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735970
R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736065

Also cite B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work). Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

@misc{orchid_phase_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}